Internet Protocol Version Four

Internet Protocol:- Communication between hosts can happen only if they can identify each other on the network. In a single collision domain (where every packet sent on the segment by one host is heard by every other host) hosts can communicate directly via MAC address.MAC address is a factory coded 48-bits hardware address which can also uniquely identify a host. But if a host wants to communicate with a remote host, i.e. not in the same segment or logically not connected, then some means of addressing is required to identify the remote host uniquely. A logical address is given to all hosts connected to the Internet and this logical address is called Internet Protocol Address.

The network layer is responsible for carrying data from one host to another. It provides means to allocate logical addresses to hosts, and identify them uniquely using the same. Network layer takes data units from Transport Layer and cuts them in to smaller unit called Data Packet.

Network layer defines the data path, the packets should follow to reach the destination. Routers work on this layer and provides mechanism to route data to its destination. A majority of the internet uses a protocol suite called the Internet Protocol Suite also known as the TCP/IP protocol suite. This suite is a combination of protocols which encompasses a number of different protocols for different purpose and need. Because the two major protocols in this suites are TCP (Transmission Control Protocol) and IP (Internet Protocol), this is commonly termed as TCP/IP Protocol suite. This protocol suite has its own reference model which it follows over the internet. In contrast with the OSI model, this model of protocols contains less layers.

Internet Protocol Version 4 (IPv4)

Internet Protocol is one of the major protocols in the TCP/IP protocols suite. This protocol works at the network layer of the OSI model and at the Internet layer of the TCP/IP model. Thus this protocol has the responsibility of identifying hosts based upon their logical addresses and to route data among them over the underlying network.

IP provides a mechanism to uniquely identify hosts by an IP scheme. IP uses best effort delivery, i.e. it does not guarantee that packets would be delivered to the destined host, but it will do its best to reach the destination. Internet Protocol version 4 uses 32-bit logical address.

Internet Protocol being a layer-3 protocol (OSI) takes data Segments from layer-4 (Transport) and divides it into packets. IP packet encapsulates data unit received from above layer and add to its own header information.

The encapsulated data is referred to as IP Payload. IP header contains all the necessary information to deliver the packet at the other end.

IP header includes many relevant information including Version Number, which, in this context, is 4. Other details are as follows:

• Version: Version no. of Internet Protocol used (e.g. IPv4).

• IHL: Internet Header Length; Length of entire IP header.

• DSCP: Differentiated Services Code Point; this is Type of Service.

• ECN: Explicit Congestion Notification; It carries information about the congestion seen in the route.

• Total Length: Length of entire IP Packet (including IP header and IP Payload).

• Identification: If IP packet is fragmented during the transmission, all the fragments contain same identification number. to identify original IP packet they belong to.

• Flags: As required by the network resources, if IP Packet is too large to handle, these ‘flags’ tells if they can be fragmented or not. In this 3-bit flag, the MSB is always set to ‘0’.

• Fragment Offset: This offset tells the exact position of the fragment in the original IP Packet.

• Time to Live: To avoid looping in the network, every packet is sent with some TTL value set, which tells the network how many routers (hops) this packet can cross. At each hop, its value is decremented by one and when the value reaches zero, the packet is discarded.

• Protocol: Tells the Network layer at the destination host, to which Protocol this packet belongs to, i.e. the next level Protocol. For example protocol number of ICMP is 1, TCP is 6 and UDP is 17.

• Header Checksum: This field is used to keep checksum value of entire header which is then used to check if the packet is received error-free.

• Source Address: 32-bit address of the Sender (or source) of the packet.

• Destination Address: 32-bit address of the Receiver (or destination) of the packet.

• Options: This is optional field, which is used if the value of IHL is greater than 5. These options may contain values for options such as Security, Record Route, Time Stamp, etc.

Internet Protocol hierarchy contains several classes of IP to be used efficiently in various situations as per the requirement of hosts per network. Broadly, the IPv4 system is divided into five classes of IP Addresses. All the five classes are identified by the first octet of IP.

Internet Corporation for Assigned Names and Numbers is responsible for assigning IP.

The first octet referred here is the left most of all. The octets numbered as follows depicting dotted decimal notation of IP:

The number of networks and the number of hosts per class can be derived by this formula:

When calculating hosts’ IP, 2 IP are decreased because they cannot be assigned to hosts, i.e. the first IP of a network is network number and the last IP is reserved for Broadcast IP.

Class A Address

The first bit of the first octet is always set to 0 (zero). Thus the first octet ranges from 1 – 127, i.e.

Class A addresses only include IP starting from 1.x.x.x to 126.x.x.x only. The IP range 127.x.x.x is reserved for loopback IP addresses.

The default subnet mask for Class A IP address is which implies that Class A addressing can have 126 networks (27-2) and 16777214 hosts (224-2).

Class A IP address format is thus: 0NNNNNNN.HHHHHHHH.HHHHHHHH.HHHHHHHH

Class B Address

An IP address which belongs to class B has the first two bits in the first octet set to 10, i.e.

Class B IP range from 128.0.x.x to 191.255.x.x. The default subnet mask for Class B is 255.255.x.x.

Class B has 16384 (214) Network addresses and 65534 (216-2) Host addresses.


Class C Address

The first octet of Class C IP address has its first 3 bits set to 110, that is:

Class C IP range from 192.0.0.x to 223.255.255.x. The default subnet mask for Class C is 255.255.255.x.

Class C gives 2097152 (221) Network addresses and 254 (28-2) Host addresses.


Class D Address

Very first four bits of the first octet in Class D IP addresses are set to 1110, giving a range of:

Class D has IP rage from to Class D is reserved for Multicasting. In multicasting data is not destined for a particular host, that is why there is no need to extract host address from the IP address, and Class D does not have any subnet mask.

Class E Address

This IP Class is reserved for experimental purposes only for R&D or Study. IP addresses in this class ranges from to Like Class D, this class too is not equipped with any subnet mask.

Each IP class is equipped with its own default subnet mask which bounds that IP class to have prefixed number of Networks and prefixed number of Hosts per network. Classful IP does not provide any flexibility of having less number of Hosts per Network or more Networks per IP Class.

CIDR or Classless Inter Domain Routing provides the flexibility of borrowing bits of Host part of the IP and using them as Network in Network, called Subnet. By using subnetting, one single Class A IP address can be used to have smaller sub-networks which provides better network management capabilities.

Class A Subnets

In Class A, only the first octet is used as Network identifier and rest of three octets are used to be assigned to Hosts (i.e. 16777214 Hosts per Network). To make more subnet in Class A, bits from Host part are borrowed and the subnet mask is changed accordingly.

For example, if one MSB (Most Significant Bit) is borrowed from host bits of second octet and added to Network address, it creates two Subnets (21=2) with (223-2) 8388606 Hosts per Subnet.

The Subnet mask is changed accordingly to reflect subnetting. Given below is a list of all possible combination of Class A subnets:

In case of subnetting too, the very first and last IP of every subnet is used for Subnet Number and Subnet Broadcast IP respectively. Because these two IP addresses cannot be assigned to hosts, sub-netting cannot be implemented by using more than 30 bits as Network Bits, which provides less than two hosts per subnet.

Class B Subnets

By default, using Classful Networking, 14 bits are used as Network bits providing (214) 16384 Networks and (216-2) 65534 Hosts. Class B IP Addresses can be subnetted the same way as Class A addresses, by borrowing bits from Host bits. Below is given all possible combination of Class B subnetting:

Class C Subnets

Class C IP addresses are normally assigned to a very small size network because it can only have 254 hosts in a network. Given below is a list of all possible combination of subnetted Class B IP address:

Internet Service Providers may face a situation where they need to allocate IP subnets of different sizes as per the requirement of customer. One customer may ask Class C subnet of 3 IP addresses and another may ask for 10 IPs. For an ISP, it is not feasible to divide the IP addresses into fixed size subnets, rather he may want to subnet the subnets in such a way which results in minimum wastage of IP addresses.

For example, an administrator have network. The suffix /24 (pronounced as “slash 24”) tells the number of bits used for network address. In this example, the administrator has three different departments with different number of hosts. Sales department has 100 computers, Purchase department has 50 computers, Accounts has 25 computers and Management has 5 computers. In CIDR, the subnets are of fixed size. Using the same methodology the administrator cannot fulfill all the requirements of the network.

The following procedure shows how VLSM can be used in order to allocate department-wise IP addresses as mentioned in the example.

Step – 1

Make a list of Subnets possible.

Step – 2

Sort the requirements of IPs in descending order (Highest to Lowest).

• Sales 100

• Purchase 50

• Accounts 25

• Management 5

Step – 3

Allocate the highest range of IPs to the highest requirement, so let’s assign /25 ( to the Sales department. This IP subnet with Network number has 126 valid Host IP which satisfy the requirement of the Sales department. The subnet mask used for this subnet has 10000000 as the last octet.

Step – 4

Allocate the next highest range, so let’s assign /26 ( to the Purchase department. This IP subnet with Network number has 62 valid Host IP Addresses which can be easily assigned to all the PCs of the Purchase department. The subnet mask used has 11000000 in the last octet.

Step – 5

Allocate the next highest range, i.e. Accounts. The requirement of 25 IPs can be fulfilled with /27 ( IP subnet, which contains 30 valid host IPs. The network number of Accounts department will be The last octet of subnet mask is 11100000.

Step – 6

Allocate the next highest range to Management. The Management department contains only 5 computers. The subnet /29 with the Mask has exactly 6 valid host IP. So this can be assigned to Management. The last octet of the subnet mask will contain 11111000.

By using VLSM, the administrator can subnet the IP subnet in such a way that least number of IP are wasted. Even after assigning IPs to every department, the administrator, in this example, is still left with plenty of IP which was not possible if he has used CIDR.

There are a few reserved IPv4 address spaces which cannot be used on the internet. These addresses serve special purpose and cannot be routed outside the Local Area Network.

Private IP

Every class of IP, (A, B & C) has some addresses reserved as Private IP addresses. These IPs can be used within a network, campus, company and are private to it. These addresses cannot be routed on the Internet, so packets containing these private addresses are dropped by the Routers.

In order to communicate with the outside world, these IP addresses must have to be translated to some public IP using NAT process, or Web Proxy server can be used.

The sole purpose to create a separate range of private addresses is to control assignment of already-limited IPv4 address pool. By using a private address range within LAN, the requirement of IPv4 addresses has globally decreased significantly. It has also helped delaying the IPv4 address exhaustion.

IP class, while using private address range, can be chosen as per the size and requirement of the organization. Larger organizations may choose class A private IP address range where smaller organizations may opt for class C. These IP addresses can be further sub-netted and assigned to departments within an organization.

Loopback IP

The IP range – is reserved for loopback, i.e. a Host’s self-address, also known as localhost address. This loopback IP is managed entirely by and within the operating system. Loopback addresses, enable the Server and Client processes on a single system to communicate with each other. When a process creates a packet with destination address as loopback address, the operating system loops it back to itself without having any interference of NIC.

Data sent on loopback is forwarded by the operating system to a virtual network interface within operating system. This address is mostly used for testing purposes like client-server architecture on a single machine. Other than that, if a host machine can successfully ping or any IP from loopback range, implies that the TCP/IP software stack on the machine is successfully loaded and working.

Link-local Addresses

In case a host is not able to acquire an IP from the DHCP server and it has not been assigned any IP manually, the host can assign itself an IP address from a range of reserved Link-local addresses. Link local address ranges from —

Assume a network segment where all systems are configured to acquire IP from a DHCP server connected to the same network segment. If the DHCP server is not available, no host on the segment will be able to communicate to any other. Windows (98 or later), and Mac OS (8.0 or later) supports this functionality of self-configuration of Link-local IP. In absence of DHCP server, every host machine randomly chooses an IP from the above mentioned range and then checks to ascertain by means of ARP, if some other host also has not configured itself with the same IP. Once all hosts are using link local addresses of same range, they can communicate with each other.

These IP addresses cannot help system to communicate when they do not belong to the same physical or logical segment. These IPs are also not routable.

The Best Internet Marketing Training Program Online

Are you wondering what the best internet marketing training program online is? Well I have to say, being an internet marketing consultant, I’ve came across a wide variety of programs out there. I’ve being practicing online marketing since 2004, so I’ve seen the old school gurus, and the new school heroes of today’s current time. And I can honestly say, the program quality is VASTLY different.

The old school internet marketing training programs aren’t as software and technologically driven as today’s programs are. Back in the day, you would learn hard hitting strategies that really improved your website sales immediately. I want to share a personal story about a free internet marketing program I came across while I was in college – and it changed my life completely.

So I was in college trying my best to make money in between classes, and I was doing the direct linking method of marketing. Back then you had traditional pay per click advertising search engines such as Overture, MSN Adcenter, and Google AdWords. Those were the top 3 – before Yahoo and MSN (currently Bing) merged. So I was in college linking directly to my ugly sales letter page, and getting no results. Well actually, the only results I was getting was bad results.

I read every single article you could think of, and I came across a guy named Terry Dean. I read his article, was intrigued, and saw a link for a free book he had. The book was called something like, “10 Quick And Easy Ways To Boost Your Website Sales In A Week” (or something like that). I read it, and it changed my entire marketing completely.

1 week after implementing his ideas and applying changes to my website, I got my first 2 sales ever. I fell out of my chair. I couldn’t believe it. I said this “internet thing” is real and I wanted more. Now fast forward to this day of age and the internet marketing training that I see is ridiculous. Everybody has a new secret or a new technique. Everybody’s trying to get rich overnight WITHOUT a website.

There are a lot of internet marketing training programs these days that teach people to get started with affiliate marketing and just “share” their link on Facebook, forums, and search engines. This doesn’t work, and the old school marketers look at these promotional tactics and authors as if they are scammers. Why do I use the word “scammer”? Well it’s simple.

Everywhere you go, everyone has a “new” way of doing something. Everything has to be faster, better, and more supreme than the proven way of making money. This is why so many people fail, because they think they can just put up a website, put their link into an autoblaster, and get rich overnight. It doesn’t work like that. Even worst is when people join an affiliate network, sign up to promote a particular product, and then just blast their affiliate link all over the place.

And yes, there are high priced internet marketing training programs that advise this kind of marketing. It’s frightening isn’t it? It makes new age marketers like myself look bad and frowned upon, because my methods work, and it doesn’t take a genius to implement them and see results. Whenever you come across an internet marketing training program, you have to keep an eye out for a few things.

You should look to see if the person has something free to offer you – to sample. This way you can “test drive” their expertise, and take a peek to see what they have to say. Then you should be able to take what you’ve learned from their free sample, and be able to apply it to your business. This is crucial, because just because you pay for an internet marketing program, doesn’t mean you’re going to learn the important stuff.

There’s a well-known marketer online (who’s name I won’t disclose) who had an online business program. He had tons of testimonials from people who used his strategies and were making thousands of dollars per month. Some of them were making thousands of dollars per day. Actually… some of them were making over $10,000 per day – and they attributed their success to this guy’s course.

So I bought the course for $39 (out of intrigue), and what did I find? I found a glorified sales pitch to purchase his $995 “advanced course” about making money on the internet. The material in the course that I bought only talked about why most people aren’t making money online, and how people promote products that they want to promote – INSTEAD of selling what people are looking for.

Who doesn’t know that? What business owner would sell something that nobody desires? This is simple market research. So I bought the $39 course and was highly disappointed, and quite mad because of the testimonials that I saw that were associated with this course. So these are some of the games and gimmicks some of the new age “gurus” like to play in order to boost their bank account, and take advantage of people.

So this was certainly not the best internet marketing training program I’ve seen. The old age internet marketer’s actually delivered when it came to value, and that is why they are legendary and are in the “hall of fame” of marketing. Nowadays you can go to YouTube and find over 100 gurus who have an internet marketing “success system” that is unique from everybody else’s. If you take a look at the ads, they all sound the same. And when you buy the products, most of them is just rehashed information.

There are a lot internet marketing training programs on the internet, and you can’t trust just anybody. If you’re going to follow someone, make sure they have a real website – and not just an ugly affiliate link. Make sure they have an email newsletter that you can subscribe to and learn from. Make sure they have training articles and free materials that you can learn from. Make sure you can reach them by email and via social media. And make sure they are current and on top of the latest trends in the internet marketing industry.

Be careful who you buy from, because you might end up disappointed like I was.

Who Invented the Internet – What Is the Future?

Before the Internet was actually the Internet, it was called ARPAnet. ARPA-Who? Yes, it’s a funny sounding name for sure. Especially considering what the Internet is today, literally encompassing every aspect of our lives. ARPAnet is an acronym for Advanced Research Projects Agency Network. In the late 1960s, The Advanced Research Projects Agency and the Department of Defense set out on a mission. They were trying to find a way to simplify communication and share data, but not using the old telephone method of ‘circuit switching’ to transfer voice and data communications. That method was only able to send from one to another in a linear fashion – from end to end.

The ARPAnet once set up, as rudimentary as it was in the beginning (late 70’s, early 80’s) used packet switching which enabled the sending and receiving of communication and data to multiple locations. Thus, TCP/IP communication protocols were born. You can probably thank Robert Kahn and Vint Cerf, often referred to as the Father of the Internet, for that. What started out as a defense project quickly expanded to the National Science Foundation (NSF) and academia – which allowed the sharing of information in real time. In 1989 ARPAnet was shut down, replaced by NSFnet.

First Commercial Use of the Internet

The first public and commercial use of the Internet came when in mid-1989 when Compuserve and MCImail added email service for anyone who wanted it. Next, PSInet setup a commercial section to the Internet backbone. Then by the end of 1990 Tim Berners-Lee came up with HyperText Transfer Protocols, and that should sound very familiar to everyone; HTTP. Next came; HTML, UseNet, and FTP (File Transfer Protocol). The Internet was up and running, and only in their wildest dreams would they have imagined that today just over 4 Billion people are now connected online across the globe – soon everyone will be connected and their lives affected in some way.

The Internet Has Changed the Way We Do Business Forever

Before the Internet, businesses were using fax machines, Federal Express package delivery and Zap Mail, Snail Mail (USPS), and very limited data transfer with Alpha Pagers (very brief text messages for which you could answer Y or N for yes or no). At that time people were upset with Junk Fax advertising, little did they know the future of SPAM was going to take a big bite out of that nonsense – albeit, only to make it a 1,000 times worse. Before SPAM blockers, users wore the letters off the “delete” key within a month after buying a new computer.

The Internet sped up the flow of information and the speed of business to the point that in 1999 Bill Gates wrote a book; Business @ The Speed of Thought. Of course, by the mid-1990s nearly every legitimate business, big and small, either had or was building a website. Why not have an online brochure available 24/7 without having to print and mail out information to potential customers? Yes, the printing industry suffered, print shops across the nation were going out of business, almost as fast as the film-developing sector disappeared with the advent of digital cameras.

The Major Evolutionary Shifts of Commercial Internet Use

Yes, the Internet has changed everything in our world, but nowhere is the shift as dramatic as it is in the business world. From 1990 to 2000, within 10-years everything had changed. It was a chaotic time, yet a time for significant opportunity. There is always opportunity in change. The more rapid the change the more chaos, crisis, and yes, opportunity. Below is a quick list of some of the paradigm shifts the Internet has brought to business;

  1. Commercial E-mail became the preferred method of written communication
  2. Companies, regardless of size, built websites – competing on a level playing field
  3. Interactive websites allowed customers and businesses to conduct business online
  4. Industry Portal Websites sprung up with information in every sector of the economy
  5. Search Engine competition rapidly evolved to serve the instant information needs of consumers
  6. Bulletin Boards then Blogs, brought 2-way open transparent information for business communication
  7. Social Networks and Social Business Networks began to grow
  8. The whole world went mobile with smartphones – the Internet followed – the rest is history

Today, the world’s information is at your finger-tips wherever you are and whenever you want it. Soon, the SpaceX LEO (Low Earth Orbit) Satellite Network System, Starlink will deliver Internet Service to anywhere on the planet, and anyone with a mobile device will be able to access the Internet. Well, that just changes everything, and here we go again. Are you ready for the next wave of opportunity/chaos, aboard the next satellite rocket launch? It’s already here, and deployed. It will come online in 2020. Once again, the Internet does not disappoint – change is the Internet’s only constant. Your business should be constantly exploiting these new technologies

What’s Comes Next? What’s the Next Big Evolution for Business Computing?

This turns out to be an easy one to predict, as industry and the world’s largest corporations are already preparing. Consider if you will The Internet of Things (IoT), Big Data, and AI (Artificial Intelligence) all connected in real time to the cloud, and all that secure data and information ready for anyone anywhere on any mobile device?

Imagine running a factory, supply chain, construction project, hospital, university, financial institution or multiple retail locations and having the exact pertinent information you need instantaneously? Imagine all those systems integrated, systematized, and optimally configured for maximum efficiency – on any job site, location, and the ‘need to know’ information for each team member in real-time.

From a business perspective, the Internet just got a 100-times more useful, but only if you take advantage of these changes and opportunities.